Diorganotin di(thio carboxylic acid esters) and the preparation thereof



United States Patent i 3,525,761 DIORGANOTIN DI(THIO CARBOXYLIC ACIDESTERS) AND THE PREPARATION THEREOF Tosliio Saki, Osaka-ski, andKozaburo Suzuki, Kobe-shi, Japan, assignors to Nitto Kasei Co., Ltd.,Osaka, Japan, a corporation of Japan No Drawing. Uriginal applicationMay 25, 1967, Ser. No. 64l,l52. Divided and this application June 25,1969, Ser. No. 852,136

Int. Cl. C07f 7/22 US. Cl. 266--429.7 4 Claims ABSTRACT OF THEDISCLOSURE Sulfur containing organotin compounds of the formula 0011msnlswl-mmoooCHrOH2oHCH ]2 prepared by the reaction of an ester and adialkyltin oxide may be used as stabilizers for resins.

This application is a division of co-pending application Ser. No.641,152, filed May 25, 1967, and now abandoned.

This invention relates to novel sulfur containing organotin compounds,to the preparation of such compounds, and to polyvinyl chlorides,copolyrners with vinyl chlorides as the main constituent, or theseresin-based polyblends, stabilized with said sulfur containing organotincompounds.

There have been heretofore used a number of different types ofsulfur-containing organotin compounds known as stabilizers for theseresins (as are disclosed in Japanese patent publications Nos. 789/57,and 5,282/59), but these conventional stabilizers may be characterizedby unsatisfactory stabilizing ability because of volatilization duringthe process of producing resins at elevated temperatures, and since theypossess a sharp odor characteristic of mercaptan, not only do they makeoperators feel uncomfortable, but they often give a bad influence to thehuman body. In addition, as these stabilizers may not prevent a resinouscomposition containing same from adhering to a roll, and also may notreduce a gelling time, it is hard to conduct operations efliciently orhandily for prolonged periods of time without the aid of supplementarystabilizers. Furthermore, halogen containing resins often undergo achange of physical properties (e.g., increasing of fragility) by theaddition of these sulfur containing organotin com pounds.

According to the present invention, these adverse effects may be reducedor eliminated by employing a new class of sulfur containing organotincompounds as stabilizers.

it is an object of this invention to provide novel sulfur containingorganotin compounds and methods of producing such compounds. A furtherobject of this invention is to provide polyvinyl chlorides, copolymerswith vinyl chlorides as the main constituent, or these resin-basedpolyblends, stabilized With these novel sulfur containing organotincompounds. Other objects will be apparent to those skilled-in-the-artfrom the following description.

In accordance with certain of its aspect, the method of this inventionfor stabilizing polyvinyl chlorides, copolymers with vinyl chlorides asthe main constituent, or these resin-based polyblends against thedeteriorating effects of heat and light comprises incorporating intosaid halogen containing vinyl resins an inhibiting amount of a sulfurcontaining organotin compound having the following formula Patented Aug.25, 1970 wherein R is alkyl of 18 carbon atoms, and m represents 1 or 2.

Since a sulfur containing organotin compound employed in the inventionhas two other linkages in its molecule, it is less volatile than theconventional stabilizers, and the liability of the sulfur containingorganotin compound in a resin composition to escape therefrom is muchless than that of the conventional stabilizer. The low volatility of thesulfur containing organotin compounds make them especially useful asstabilizers in halogen containing vinyl resin formulations which requireheat or exposure to elevated temperatures during use or during theprocessing of the halogen containing vinyl resin material. At the sametime, since the sulfur-containing organotin compounds have both esterand other linkages in their molecules, these novel stabilizers mayexhibit a good compatibility with resins and an accelerated gelation;they may make the lowest processable temperature of resins reduced about5 C. compared with the conventional stabilizers; and resin compositionscontaining said novel stabilizers may perform over longer periods oftime during the heat processing of same. A new class of these compoundsalso may impart an improved satisfactory stabilizing effect againstdegradation by light to resins compared with the conventionalsulfur-containing organotin compounds which are unstable to light.Besides, there is not practically a disgusting smell of mercaptaneduring the process of producing stabilized resins, and consequently theydo not affect badly to a person.

In accordance with certain aspects of this invention, the method ofpreparing sulfur-containing organotin compounds comprises the steps of(a) reacting 3-methoxybutan0l with a rnonomercaptocarboxylic acidselected from the group consisting of thioglycolic acid andmercaptopropionic acid by the conventional method to form an ester,

(b) heating with stirring said ester and a dialkyltin oxide selectedfrom the group consisting of dimethyltin oxide, dibutyltin oxide,diamyltin oxide, and dioctyltin oxide in the presence (or absence) of aninert solvent, and

(c) removing water formed in the reaction.

Only an inhibiting amount of organotin compound is required. Preferably,the amount of the sulfur containing organotin stabilizers to be employedin the process of this invention is in the range of 0.1 to 10 parts byweight per parts by weight of the resins. The stabilizers may be usedsingly or in combination, and they may also be used together with otherknown stabilizers, and with other additives such as a mold lubricant, anantioxidant, and a U.V. absorber.

EXAMPLE 1 A three-nooked flask, equipped with a stirrer and a Dean trap,was charged with 1.1 mole of thioglycolic acid, 1 mole of3-methoxybutanol, 200 ml. of benzene as solvent, and 2.5 g. ofp-toluenesulfonic acid as esterification catalyst. This mixture wasreacted by the conventional method to form 168 g. (94.5%) of3-methoxybutyl thioglycolate,

A three-necked flask, equipped with a stirrer and a Dean trap, wascharged with 1 mole of said ester, 0.5 mole of dibutyltin oxide, andbenzene as solvent. This mixture was heated with stirring until all theWater of reaction was removed. The benzene was then distilled off underreduced pressure to yield 290 g. (98.5%) of dibutyltin-bis-(3-methoxybutyl thioglycollate) (A). The product is a 4 light yellow,transparent liquid. The physical properties: pressure to yield 354 g.(97.3%) of dioctyltin bis-(3- n =l.5128; D =l.271. methoxybutylmercaptopropionate) (C). The product is a Analysis.-Calculated(percent): Sn, 20.2; S, 10.9; C, light yellow, transparent liquid. Thephysical properties: 45.0; H, 7.5. Found (percent): Sn, 20.6; S, 10.7;C, 45.3; n =l.5039; D =l.257. H, 7.4. 5 Analysis.--Calculated (percent):Sn, 16.31; S, 8.8; C, To 100 parts by weight of polyvinyl chloride (mean52.8; H, 8.9. Found (percent): Sn, 16.9; S, 9.1 C, 53.0; polymerizationdegree: 1,100) was added 2 parts by H, 8.0.

weight of said dibutyltin-bis-(3-methoxybutyl thioglycol- To 100 partsby weight or copolymer consisting of late) (A). The mixture was sheetedby milling for 5 min- 95% by weight of vinyl chloride and 5% by weightof utes on a mixing roll heated to 160 :2 C. For comparavinyl acetatewas added 3 parts by weight of said dioctyltive purposes, by the sameprocedure, a sheet was made tin-bis-(3-methoxybutyl mercaptopropionate)(C). The containing 2 parts by weight of dibutyltin didodecyl mermixturewas sheeted by milling for 5 minutes on a mixing captide, (C H Sn(SC I-I(B) as prior art sulfur conroll heated to 150i2 C. For comparativepurposes, taining stabilizer in place of the stabilizer of this invenbythe same procedure, a sheet was made containing 3 tion. 15 p rts byweight of dioctyltin-bis-(octyl thioglycollate), The obtained sheetswere tested in a Geer oven heated (C H Sn(SCH COOC H (D) as prior artsulfur to 180 C. for heat stability, and the discoloration wascontaining stabilizer in place of the stabilizer of this inobserved. Thesame sheets prepared for a weathering test vention. were irradiated for500 hours in a weatherometer, The obtained sheets were tested in a Geeroven heated equipped with a xenon lamp screen by a heat resisting to 180C. for heat stability, and the discoloration was optical glass filter inorder to cut oif ultraviolet rays below observed. The same sheetsprepared for a weathering test the wavelength of 279 my, and thediscoloration and the were irradiated for 500 hours in a weatherometer,deterioration other than that in appearance were observed. equipped witha xenon lamp screened by a heat resisting For volatility the stabilizerswere tested by weighing preoptical glass filter in order to cut offultraviolet rays cisely each of compounds (A) and (B) in dishes (5 cm.below the wavelength of 279 m and the discoloration in diameter x 3 cm.in height); heating the dishes to 180 and the deterioration other thanthat in appearance were C. in a Geer oven for 1 hour; and measuring theweight observed. For volatility the stabilizers were tested by loss.Results are shown in the following Table I. weighing precisely each ofcompounds (C) and (D) in TABLE I Test for weatherability Test for heatstability-Color of sheet after- Heating 1055 Color of sheet Appearanceof of stabilizer Stabilizer 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 500hrs. sheet after 500 hrs. (percent) (A) Colorless Colorless ColorlessLight yellow Colorless Transparent 0.8 (B) do do Light yellow YellowBrown Turbid 3. 0

Moreover, in order to prove a good workability of dishes (5 cm. indiameter x 3 cm. in height); heating the resinous composition containingthe stabilizer of this indishes to 180 C. in a Geer oven for 1 hour; andmeasurvention, a test was conducted to determine the lowest posing theweight base. Results are shown in Table II.

TABLE 11 Test for Weatherability Test for heat stabllltyColor of sheetaiter- Heating loss Color of sheet Appearance of of stabilizerStabilizer 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 500 hrs. sheet after500 hrs. (percent) (O) Colorless Colorless Light yellow Light yellowColorless Transparent 0.6 1 -rln rln ..do Yellow Brown Opaque 2.5

sible surface temperature of a roll at that a completely Moreover, inorder to prove a good workability of gelatinated transparent sheet mightbe obtained. Processresinous composition containing the stabilizer ofthis ining at 145 C. was sufficient to mtke such a sheet in the vention,a test was conducted to determine the lowest case of using stabilizer(A), the sheet being not discolored possible surface temperature of aroll at that a comafter blending for 1 hour; Whereas, in the case ofusing pletely gelatinated transparent sheet might be obtained.stabilizer (B), processing even at 150 C. was not sufii- Processing at145 C. was sufficient to make such a sheet, cient, the sheet turningyellow after blending only 35 minnot discolored after 1 hour blending,in the case of using utes. It is a great advantage to be able to lower aprocessstabilizer (C); whereas, in the case of using stabilizer ingtemperature by 5 C. in the process of molding heat (B), processing ovenat 150 C. was not suificient, the sensible polyvinyl chlorides. sheetturning yellow after the resinous composition was EXAMPLE 2 blended only28 minutes. It is a great advantage to be able to lower a processingtemperature by 5 C. 1n the A three-necked flask, equipped with a ti d aDean process of molding heat sensible polyvinyl chlorides. trap, wascharged with 1.1 mole of mercaptopropionj Although this invention hasbeen illustrated by referacid, 1 mole of 3-methoxybutanol, 200 ml. ofbenzene as on e to specific examples, numerous changes and modifil d 25of -tolu nesulfonjc id t t ifi cations thereof which clearly fall withinthe scope of the tion catalyst. This mixture was reacted by theconventional ion W ll be apparent to those skilled in the art. method toform 186 g. (96.9%) of B-methoxybutyl mer- W t s claimed is:captopropionate, 1. The compound having the fOIIl'llllB.

OCH; CH CH CHE-CH) OCHB (HSGHZCHZOOOCHZ 2 2 a R2 H2)mCOOCHzCHzlH-CHQ Athree-necked flask, equipped with a stirrer and a Dean trap, was chargedwith 1 mole of said ester, 0.5 mole of diwherein R is alkyl of l-8carbon atoms, and mi represents octyltin oxide, and benzene as solvent.This mixture was 1 or 2. heated with stirring until all the Water ofreaction was re- 2. The compound as claimed in claim 1,dibutyltin-bismoved. The benzene was then distilled oil under reduced(3-methoxybutyl thioglycollate).

6 References Cited UNITED STATES PATENTS 2,832,750 4/1958 Weinberg260429.7 X 3,029,267 4/1962 Berenbaum et a1. 260-429] 3,478,071 11/1969Weisfeld 260429.7

TOBIAS E. LEVOW, Primary Examiner W. F. W. BELLAMY, Assistant ExaminerU.S. Cl. X.R. 26045.75

